Pallet rack



Dec. 25, 1962 T. J. FULLERTON ETAL PALLET RACK 2 Sheets-Sheet 1 Filed June 30, 1960 4 1 F3 5 2 w 22 w w y 7/ f a wwwew wwwwwwwwwwwfiwi m wmmnfimmwww 0 & H 1 W5 M 6 w fl V A u l l mh f tr iw Dec. 25, 1962 T. J. FULLERTON ETAL 3,070,237

PALLET RACK Filed June 30, 1960 2 Sheets-Sheet 2 States atet 3,079,237 PALLET RACK Thomas J. Fullerton, Palos Heights, and William Schroeder, Evanston, Ill., assignors to Acme Steel Company, Chicago, TIL, a corporation of Illinois Filed June 30, 1960, Ser. No. 40,060 Claims. (Cl. 211-447) This invention relates to the art of support structures, particularly to a collapsible shelf structure adapted for supporting palletized loads, of a type commonly referred to as a pallet rack.

The use of pallets or skids as supports for loads of all varieties of materials has been on the increase in recent years. The skid or pallet not only supports the load, but it permits the forks of a lift truck to be inserted below it in order to allow the palletized load to be conveniently transported from place to place as required. Due to the increased use of palletized loads, a definite need arose for a supporting structure which can support a maximum number of palletized loads in a minimum space at a minimum cost.

Structures for this purpose have been developed. They are generally in the form of vertical upright members joined together by horizontal side to side and front to back members which form an open type skeletal structure. The vertical members are made long enough to support the horizontal members at vertically spaced intervals to provide a multi-t-iered structure for supporting palletized loads at different stacked levels. Also, the vertical members are spaced horizontally from each other by calculated amounts to establish bays of given length to accommodate a given number of palletized loads in a row without waste of space on the pallet rack structure. Within reason, the structures can be made of any length and any height depending upon the particular storage space available.

It seems that one of the most desirable requirements for a pallet rack structure is that it should be capable of being assembled and disassembled conveniently with a minimum of time and effort. It must also be rigid when assembled and not subject to accidental disassembly.

Another desirable feature is to have a minimum of parts and, if possible, no extra detachable parts which can be misplaced, such as connector pins. Another desirable objective is to have maximum load bearing support between the structural members in different contact planes with means to resist beam rotation, if possible.

No single pallet rack structure now available embodies all of these optimum features. It is therefore the principal object of this invention to provide an improved pallet rack structure embodying all of the above mentioned advantages.

In order to achieve this objective, a pallet rack structure is provided wherein there are only two basic components, the vertical supports or uprights and horizontal beams. These are no other separate parts which can be detached and misplaced. The connections between the uprights and the beams are by flanged lugs projecti g from flanged ends of the beams where they can be easily engaged in slanted key hole slots in the uprights and wedged into tight engagement therewith. The flanges on the beam ends are bent at right angles so that they make contact with the uprights along two difierent planes. A very significant feature is a releasable bolt or latch at each end of the beams which is engaged with the upright to provide a safety means for preventing accidental removal of the beams once in place and which provides additional bearing support in a plane different than the principal plane of bearing support by the flanged lugs on the beams. The bolt, by providing a bearing support in this additional plane, also provides means for resisting rotation of the beams in place.

Other objects and advantages of the invention should be apparent upon reference to the accompanying drawings in which:

FIG. 1 shows a perspective view of a partially cutaway pallet rack structure embodying the features of this invention;

FIG. 2 shows a partially cutaway and enlarged sectional view of a portion of the pallet rack structure of FIG. 1 showing the region of connection between the end of a beam and an upright member;

FIG. 3 shows a partially cutaway and sectional elevation view of a beam connected to an upright;

FIG. 4 shows a sectional view along the line 4-4 of FIG. 3;

FIG. 5 shows a view along the line 5-5 of FIG. 3;

PEG. 6 shows an enlarged sectional view along the line 6-6 of PEG. 3 and particularly shows the shape of one of the flanged connector lugs; and

H6. 7 shows a sectional view along the line 7-7 of As viewed in FIG. 1, a typical support structure or pallet rack 1 consists of a pair of ladder-shaped upright frames 2 and 3 spaced apart from each other and joined together by means of horizontal beams 4, 5, 6 and 7. These beams are joined at their ends to the upright frames 2 and 3 in a manner hereinafter described. The upright frame 2 is also joined to the ends of other horizontal beams 8, 9, it) and 11 which, although not shown, extend to an additional spaced upright frame similar to frames 2 and 3. In this manner the entire pallet rack 1 can be made any length required. Just as the beams 8, 9, 1t) and 11 extend from the frame 2, other beams can extend in the opposite direction from the frame 3 so that the pallet rack can be extended in length in either direction. I

Each of the upright frames 2 and 3 consists of a front upright 12 and a rear upright 13 joined together by horizontal front to back members 14- and 15 and diagonal braces 16 and 17. Naturally the lengths of the members 14, l5, l6 and 17 can be appropriately cut to space the uprights 12 and 13 as far apart as necessary to provide the proper span between the front beams 4 and 5 and the rear beams 6 and '7. Also, the uprights 12 and 13 can be made as tall as necessary in order to accommodate the required vertical spacing of the horizontal beams, as well as to permit positioning of as many vertically spaced beams as desired. Also, additional members similar to 14-, 15', 16 and 17 can be added to provide sufiicient rigidity and strength.

With the structure as shown in FIG. 1, the beams 5 and a provide a span across which pallets or other articles can span so that the beams act as their support at an upper level. Similarly the beams 4. and 7 provide a spanned support for pallets or other objects at a lower level. A pallet 18- is shown supported by the beams 4 and 7 and also a board 19*. If continuous shelving is required so that objects will not fall through the spanned opening between the beams, a plurality of boards 19 can be positioned side by side along the beams to provide a continuous uninterrupted support for various shapes and sizes of objects.

The front to back members 14 and 15 and diagonal braces 16 and 17 are preferably welded at their ends to the uprights l2 and 13 in order to provide the completed ladder-shaped upright frames 2 and 3. This enables the frames 2 and 3 to be shipped as integral units, thus saving erection time and also insuring a rigid structure which might not be obtained if nuts and bolts or other fastening means are used to secure these members together.

Each of the uprights 12 and 13 is provided with two rows of first openings 2d extending along the entire length of the front walls 21 of the uprights. The openings are equally spaced from each other by a fixed increment. Each of the uprights 12 and 13 is also provided with a row of equally spaced openings 22 along opposite side walls 23 and 24 of the uprights. These side walls 23 and 24 are positioned parallel to each other and are connected therebetween by the front wall 21 which forms the upright into a channel shape. The side Walls 23 and 24 are provided with flanges 25 and 26 which extend toward each other in a plane parallel to the front wall 21 of the upright. The flanges 25 and 25, the side walls 23 and 24 and the front wall 21 together provide a flanged channel-shaped upright with four corners 27, 28, 29 and 31 which impart column strength and rigidity to the up rights.

Even though different number designations have been given to the horizontal beams, they are all identical in structure and can be used interchangeably as front or back beams by merely rotating them 180 end to end in a horizontal plane.

As shown in FIGS. 1, 2, 3, 4 and 5, a horizontal beam 6 consists of an L-shaped tube 31 composed of two channels 32 and '33 facing each other with their flanges 32a, 32b and 33a, 331:, respectively, overlapping each other to form a closed tube (FIG. 4). The overlapping flanges 32a, 32b, 33a and 33b are preferably welded together to maintain the channels 32 and 33 joined together and to impart strength to the assembled tube.

This tube 31 is welded at each of its ends to one wall 34 of an L-shaped end flange 35. The other wall 36 of the end flange 35 is provided with two inwardly extending flanged lugs 37 which are in fixed positions on the end flange 35. In FIGS. 6 and 7 it is shown that each of these flanged lugs 37 is provided with a cylindrical body portion 37a having two flats 3715. A hole 38 is provided in the wall 36 of the end flange which is of the same shape as the body portion of the flanged lug in the region of the flats 37b. The reason for this particular shape of the body portion of each of the lugs 37 is to prevent rotation of the lug after it is once in place. When in place, the lug bottoms in the opening 38 against shoulders 37c produced by the cutout of the flats 37b. With the lugs 37 properly bottomed, their ends 39 are peened over as if riveted.

The reason for not allowing rotation of the lugs 37 in the openings 38 is because the flange 49 on the free end of each of the lugs is eccentric of the lug so that the flange does not extend above the lug. but only below it. The reason for this is to prevent the flange 40 from being caught on the upper end of an opening 20 when the apparatus is being disassembled.

In order to assemble a horizontal beam to an upright 12 or 13, the beam is extended horizontally and its L- shaped end flange 35 is brought to bear against the front wall 21 and a side wall 23 or 24 of an upri ht. In order to do this the lugs 37 on the flange are aligned to pass through the openings 29 in the upright. These openings 20 are somewhat key-shaped, having an enlarged circular portion 26a intersecting a narrow elongated portion 205 which is slightly canted toward the center of the upright. Having two rows of these holes 20, the effect is that these elongated portions 2% are canted or sloped toward each other. Also, a hole 20 in one row is positioned immediately opposite a hole 20 in the adjacent row. Since there is equal spacing between all of the holes, each is positioned with another immediately adjacent to it laterally. The enlarged circular portion 201! is of a diameter larger than the diameter of the flanges 4% of the lug 37 so that the lug 37 can freely fit through it. The body portion 37:: of the lug is slightly smaller than the width of the elongated hole portion 2% so that the lug can be dropped down into the elongated portion 2012 after it has been passed through the circular til portion Zita. Because of the particular dimensions of the end flange 35 and the positions of the lugs 37 thereon, as the lugs of the flange slide down the incline of the elongated portions 2iib of the holes 28, the wall 34 of the end flange is brought to bear tightly against a side Wall 23 or 24 of the upright 12 or 13. These lugs 37, therefore, provide bearing support for the horizontal beam 6 along the plane of the front wall 21 of the upright 13. By drawing the wall 34 of the end flange 35 snugly against the side wall 23, this provides a fairly rigid connection between the horizontal beam 6 and the upright 13.

In order to further enhance the rigidity of the structure, the horizontal beams 4, 5, 6 and 7 are all provided with sliding bolts 41. Each sliding bolt 41 is of L-shape having a handle length 42 connected at right angles to a body portion 43. The body portion 43 is mounted through a circular opening 44 of slightly larger diameter than the circular shape of the bolt 41 so that the bolt is freely slidable therethrough. The hole 44 is in an S- shaped support 45 which is welded to the wall 34 of the end flange 35. The end flange 34 is also provided with a hole 46 of the same diameter as the hole 44 so that the bolt 41 is ordinarily suspended through these two holes 44 and 46. The handle 42 of the bolt projects out of an L-shaped opening .7 in the side wall of the tube 31. This L-shaped hole 47 has a horizontal length 47:: into which the bolt can be shifted in order to retract it to its inner position as indicated in bold outline in FIGS. 2 and 5 where its end 41:: is recessed completely within the beam. The hole 47 is provided with a downwardly extending portion 47b into which the handle 42 can be moved or dropped by gravity in order to maintain the bolt 41 in its extended position as indicated in phantom lines in FIG. 2 and in bold outline at the left hand side of FIG. 3. The subject matter specifically relating to the bolt support 45 and its relationship to the beams supporting it is not claimed in this application, but is contained in a subsequently filed application of George E. Rasmussen, Serial Number 50,617, filed August 19, I960.

When the beam 6 is in position as shown in FIGS. 2 and 3, and the wall 34 of the end flange 35 is drawn up tightly against the wall 23 of the upright, the bolt 41 is extended so that its end 41a projects out through the hole 46 of the end flange 35. With the parts positioned as indicated, one of the second holes 22 is ali ned with the end 41a of the bolt 41. This positioning of the h les 22 is predetermined. With one of these holes 22 lined up with the end 41a of the bolt 41, extension of the bolt 41 through the hole 46 also extends it through the hole 22 in the upright. After this occurs, the bolt 41 then acts as a bearing support in the plane of the wall 23 of the upright which wall 23 is at right angles to the front wall 21 Where the lugs 37 are positioned for bearing support. In addition, by having support in this plane of the wall 23, there is provided a resistance to rotation of the beam on its axis which is highly beneficial. Another very important feature of this latch or bolt arrangement is that, in its extended position, the bolt 41 prevents disassembly of the beam 6 from the upright 23. This eliminates the possibility of accidental disassembly of a beam from an upright which mi ht otherwise occur as a worker manipulates his fork lift truck when arranging pallet loads on the pallet rack structure. It is conceivable that the operator can accidentally position the forks of the lift truck beneath one of the beams whereby sudden operation of the forks of the truck in an upward direction might easily disassemble a beam if not secured to the upright in the manner shown.

Although it has been thought desirable to provide bearing support in two different planes as herein shown and described, there has always been a difficulty of assembling a beam between two uprights positioned a fixed distance apart and obtain this advantage. With the uprights positioned a fixed distance apart, as they are during the assembly of a pallet rack, the walls 34 of the end flanges 35 are located approximately adjacent to the walls 23 and 24 of these spaced upright members. If the bolts 41 were permanently extended as if they were fixed lugs like lugs 37, it would be impossible to assemble the beams onto the uprights because the bolts would interfere with the positioning of the beams onto the uprights. With what has been shown and described in this invention, by having the bolts 41 retractable, it is possible to provide convenient assembly between fixed spaced uprights and still obtain bear-ing support in the additional plane.

Another important feature of the bolt 41 is that it is entirely contained within its beam in such a way that it cannot be separated from it. In this manner, there is no chance of losing it and it is always available when needed. On devices where there are separate connectors which are not integral with the beams or the uprights, there is always a chance of losing the connectors and, through inadvertency or laziness, leaving them off the connection so that an inferior connection results. In this device, the bolt 41 is always there and always positioned properly so that there is no doubt as to how to connect it and it always insures a well connected joint between the beam and its upright.

Although only a single embodiment of the invention has been shown and described, it should be clearly understood that the invention can be made in many different Ways without departing from the true scope of the invention as defined by the appended claims.

We claim:

1. A support structure comprising vertical uprights and horizontal beams, each of said beams being positioned between two of said vertical uprights spaced from each other by approximately the length of a beam, the two vertical uprights being provided with front walls facing in a direction away from the MlS of the beam and side Walls facing each other in a direction of the beam between the uprights, lugs on the ends of said beam, the uprights being provided with first openings along said front walls for engaging the lugs to provide support of the beam along said front walls, non-detachable latch bolts on the beam, the uprights being provided With second openings along said side walls for engaging said latch bolts to provide support of the beam along said side Walls, said latch bolts being movable on said beam for engagement with and release from the said second openings.

2. A support structure comprising vertical uprights and horizontal beams extending in a single general planar direction, the end of each beam being provided with an end flange, each end flange having a front wall in said planar direction connected to an end wall to impart an L-shape to the end flange, said uprights each having two side walls extending at an angle to said planar direction with a front wall in said planar direction connected between them, said L-shaped end flange being adapted to be positioned against an upright with the front wall of the end flange abutting the front wall of the upright and the end wall of the end flange abutting one of the side walls of the upright, the uprights being provided with first openings along their front walls and second openings along their adjacent side walls, the front wall of the end flange being provided with a lug for engaging said first openings, a retractable latch bolt on the beam, the end wall of the end flange having an opening through which the end of said bolt can be passed for engagement with one of said second openings when the bolt is moved on the beam each bolt being movably mounted in the beam.

3. A support structure comprising vertical uprights and horizontal beams extending in a single general planar direction, each end of each beam being provided with an end flange, each end flange having a front wall in said planar direction connected to an end wall to impart an L-shape to the end flange, each upright having a I 5 channel shape provided by a front wall in said planar direction connected between two adjacent side walls extending at an angle to said planar direction, each L- shaped end flange being adapted to be positioned against an upright with the front wall of the end flange abutting the front Wall of the upright and the end .wall of the end flange abutting one of the side walls of the upright, the upright being provided with first openings along its front wall and second openings along its adjacent side walls, the front wall of the end flange being provided with a projection for engaging said first openings, a retractable latch bolt on the beam, the end wall of the end flange having an opening through which the end of said bolt can be passed for engagement with one of said second openings, the bolt being slidably mounted on the beam between a retracted position where the end of the bolt is clear of the second openings and an extended position where the end of the bolt engages said one of the second openings.

4. The support structure defined by claim 3 characterized by, the beam having an opening in it through which a bolt portion projects where it can be grasped for bolt actuation.

5. The support structure defined by claim 3 characterized by, the beam having an opening in it through,

which a bolt portion projects where it can be grasped for bolt actuation, said opening having two portions corresponding to the retracted and extended positions of the bolt.

6. The support structure defined by claim .3 charac terized by, the beam having an opening in it through which a bolt portion projects where it can be grasped for bolt actuation, said opening having two portions corresponding to the retracted and extended positions of the bolt, the portion corresponding to the extended position of the bolt being lower than its other portion to allow said bolt portion to fall by gravity into it when aligned with it.

7. A beam for use in a supporting structure of a type having vertical uprights joined together by horizontal beams wherein the uprights are provided with first openings along their front wall and second openings along an adjacent side wall comprising, a walled body portion having an end flange at each of its ends, each end flange having a front wall connected to an end wall to impart an L-shape to the end flange, which allows the beam to be positioned against an upright with the front wall of the end flange abutting the front wall of the upright and the end wall of the end flange abutting one of the side walls of the upright, the front wall of the end flange being provided with a projection for engaging said first openings to connect the front wall of the end flange to an upright, a bolt, the end wall of the end flange having an opening through which the end of said bolt can be passed for engagement with one of said second openings to connect the end wall of the end flange to the upright, the bolt being movably mounted on the beam between a retracted position where the bolt is clear of ths second openings and an extended position where the end of the bolt can engage one of the second openings.

8. A beam for use in a supporting structure of a type having vertical uprights joined together by horizontal beams wherein the uprights are provided with first openings along their front wall and second openings along an adjacent side wall comprising, a walled body portion having an end flange at each of its ends, each end flange having a front wall connected to an end wall to impart an L-shape to the end flange, which allows the beam to be positioned against an upright with the front wall of the end flange abutting the front wall of the upright and the end wall of the end flange abutting one of the side walls of the upright, the front wall of the end flange being provided with a projection for engaging said first openings to connect the front wall of the end flange to an upright, a bolt, the end wall of the end flange having an opening 1 through which the end of said bolt can be passed for engagement with one of said second openings to connect the end wall of the end flange to the upright, the bolt being movably mounted on the beam between a retracted position where the bolt is clear of the second openings and an extended position where the end of the belt can engage one of the second openings, the walled body portion of the beam having an opening in its wall through which a bolt portion projects where it can be manually grasped for bolt actuation.

9. A beam for use in a supporting structure of a type having vertical uprights joined together by horizontal beams wherein the uprights are provided with first openings along their front wall and second openings along an adjacent side wall comprising, a walled body portion having an end flange at each of its ends, each end flange having a front wall connected to an end wall to impart an L-shape to the end flange, which allows the beam to be positioned against an upright with the front wall of the end flange abutting the front wall of the upright and the end wall of the end flange abutting one of the side walls of the upright, the front wall of the end flange being provided with a projection for engaging said first openings to connect the front wall of the end flange to an upright, a bolt, the end wall of the end flange having an opening through which the end of said bolt can be passed for engagement with one of said second openings to connect the end wall of the end flange to the upright, the bolt being movably mounted on the beam between a retracted position where the bolt is clear of the second openings and an extended position where the end of the bolt can engage one of the second openings, the beam having an opening in its wall through which a bolt portion projects where it can be grasped for bolt actuation, said opening having two portions corresponding to the retracted and extended positions of the bolt.

it). A beam for use in a supporting structure of a type having vertical uprights joined together by horizontal beams wherein the uprights are provided with first openings along their front wall and second openings along an adjacent side wall comprising, a walled body portion hav ing an end flange at each of its ends, each end flange having a front wall connected to an end wall to impart an L-shape to the end flange, which allows the beam to be positioned against an upright with the front wall of the end flange abutting the front wall of the upright and the end wall of the end flange abutting one of the side walls of the upright, the front wall of the end flange being provided with a projection for engaging said first openings to connect the front wall of the end flange to an upright, a bolt, the end wall of the end flange having an opening through which the end of said bolt can be passed for engagement with one of said second openings to connect the end wall of the end flange to the upright, the bolt being movably mounted on the beam between a retracted position where the bolt is clear of the second openings and an extended position where the end of the bolt can engage one of the second openings, the beam having an opening in its wall through which a bolt portion projects where it can be grasped for bolt actuation, said opening having two portions corresponding to the retracted and extended positions of the bolt, the portion of the opening corresponding to the extended position of the bolt being lower than its other portion to allow said bolt portion to fall by gravity into it when aligned with it.

11. A support structure comprising vertical uprights and horizontal beams, each beam being of tubular wall construction and each end of each beam being provided with an end flange, each end flange having a front wall connected to an end wall to impart an L-shape to the end flange, each upright having a channel shape provided by a front wall connected between two adjacent side walls, each L-shaped end flange being adapted to be positioned against an upright with the front wall of the end flange abutting the front wall of the upright and the end wall of the flange abutting one of the side walls of the upright, the upright being provided with first openings along its front wall and second openings along its adjacent side wall, the front wall of the end flange being provided with a pro, tion for engaging said first openings, a bolt, the end v. of the end flange having an opening through which end of said bolt can be passed for engagement with one of said second openings, the bolt being slidably mounted on the beam between a retracted position where the c d of the bolt is clear of the second openings and an extended position where the end of the bolt engages said one of the second openings, the beam having an opening in its wall through which a bolt portion projects where it can be grasped for bolt actuation, said opening having two portions corresponding to the retracted and extended positions of the bolt, the portion corresponding to the extended p.

ion of the bolt being lower than its Ciho? portion to :i 'v said bolt portion to fall by gravity into it when aligned with it, said first openings in the front wall of each upright being sloped to cause the projection engaged with one of said first openings to cam against the sides of the opening and draw the end wall of the end flange against a wall of the upright.

12. A beam for use in a supporting structure of a type having vertical uprights joined to horizontal beams wherein the uprights are provided with first openings along their front wall and second openings along an adjacent side wall comprising, a walled beam portion having a flange attached to it, each flange having a front wall connected to an end wall to impart an L-shape to the flange. which allows the beam to be positioned against an upright with the front wall of the flange abutting the front wall of the upright and the end wall of the flange abutting a side wall of the upright, the front wall of the flan e being provided with a projection for engaging one of said first openings to connect the front wall of the flange to an upright, a bolt, the end wall of the flange having an opening through which the end of said bolt can be passed for engagement with one of said second openings to connect the end wall of the flange to the upright, the bolt bei mov blv mounted on the beam between a retracted position where the bolt is clear of the second openings and an extended position where the end of the bolt can engage one of the second openings.

13. A beam for use in a supporting structure of a type having vertical up ights joined to horizontal beams wherein the uprights are provided with first openings along their front wall and second openings along an adjacent side wa l comprising a walled beam portion ha ing a flange attached to it. each flange having a front wall connected to an end wall to impart an L-shape to the flange, which allows the beam to be positioned against an upright with the front wall of the flan e abutting the front wall of the upright and the end wall of the flange abutting a side wall of the upright, the front wall of the flange being provided with a projection for engaging one of said first openings to connect the front wall of the flange to an upright, a bolt, the end wall of the flange having an opening through which the end of said bolt can be passed for engagement with one of said second openings to connect the end wall of the flange to the upright, the bol being movably mounted on the beam between a retracted position where the bolt is clear of the second openings and an extended position where the end of the bolt can engage one of the second openings, the walled beam portion having an opening in its wall through which a bolt portion projects where it can be manually grasped for bolt actuation.

14. A support structure comprising vertical uprights and horizontal beams extending in a single general planar direction, each beam being provided with a flange, each flange having a front wall in said planar direction connected to an end wall to impart an L-shape to the flange, each upright having at least a front wall in said planar direction connected to an adjacent side wall extending at an angle to said planar direction, each L- shaped flange being adapted to be positioned against an upright with the front wall of the flange abutting the front wall of the upright and the end wall of the flange abutting the side wall of the upright, the upright being provided with first openings along its front wall and second openings along its side wall, the front wall of the flange being provided with a projection for engaging said first openings, a retractable latch bolt on the beam, the end wall of the flange having an opening through which the end of said bolt can be passed for engagement with one of said second openings, the bolt being slidably mounted on the beam between a retracted position where the end of the bolt is clear of the second openings and an extended position where the end of the bolt engages said one of the second openings.

15. A support structure comprising vertical uprights and horizontal beams, each of said beams being positioned between two of said vertical uprights spaced from each other by approximately the length of a beam, the two vertical uprights being provided with a first set of walls facing in a direction away from the longitudinal axis of the beam and a second set of walls facing each other in a direction of the beam between the uprights, the "uprights being provided with beam support surfaces along said first set of walls, support means on and adjacent the ends of said beam for resting on said surfaces to provide vertical support of the beam along said first set of walls, nondetachable latches on the beam, the uprights being provided with openings along said second set of walls for engaging said latches to provide vertical support of the beam along said second set of walls, said latches being movable on said beam for engagement with and release from the said openings.

References Cited in the file of this patent UNITED STATES PATENTS 2,571,512 Youngberg Oct. 16, 1951 2,815,130 Franks Dec. 3, 1957 2,895,619 Frazier July 21, 1959 2,918,176 Bell Dec. 22, 1959 2,925,920 Skubic Feb. 23, 1960 2,932,368 Schell Apr. 12, 1960 FOREIGN PATENTS 516,708 Canada -1 Sept. 20, 1955 

